1. Field of the Invention.
The present invention relates to an umbrella, and more particularly, concerns a foldable umbrella with an improved wind-up handle for opening and closing the umbrella
2. Description of the Prior Art.
Foldable or collapsible umbrellas intended to provide a shady environment for users normally are available in large sizes. Typical of such shade-providing umbrellas are those which are used on the beach, lawn, patio, terrace and the like. Inasmuch as these larger umbrellas for shade purposes tend to be heavier and bulkier than hand-held umbrellas, it is known, and has been customary, to include a wind-up mechanism for raising and lowering the umbrella cover. Rotatable handles or cranks are commonly known for use on shade-type umbrellas, an example of which is found in U.S. Pat. No. 2,747,591. Wind-up mechanisms are also available on beach umbrellas which tilt, one such wind-up mechanism being described in U.S. Pat. No. 4,386,621.
Most beach or lawn umbrellas presently available for retail purchase include a number of components which are made to industry-wide standards by most manufacturers. For example, the long, hollow pole for supporting the umbrella is generally made to a singular specification particularly since many of these lawn umbrellas are intended to be inserted through standard holes in outdoor patio furniture. Most of the poles for such outdoor umbrellas have a nominal inside diameter of 1.25 inches (31.8 mm) and an outside diameter of 1.375 inches (35.0 mm). Another part which is common to most manufacturers of outdoor umbrellas is a shaft, such as a bolt or pin, which extends through the hollow pole for purposes of mounting the wind-up mechanism to the pole. A standard shaft for this purpose has a diameter of 1/4 inch (6.35 mm). In some instances, the diameter of the mounting shaft might be 5/16 inch (7.94 mm). Most manufacturers also use a standard cord which extends from the wind-up mechanism to a lift device for raising and lowering the umbrella cover. A nylon or other fabric-based cord having a diameter of 1/8 inch (3.2 mm) is relatively common to the umbrella industry.
Keeping in mind the aforementioned standard components and sizes, it normally takes about 28 complete revolutions of a wind-up handle to open a lawn umbrella from the closed position to the completely open position. Of course, the same number of turns is required to lower the umbrella from the open to the closed position. This many turns of the rotatable wind-up mechanism is not only tiring for the user, but also means that the raising or lowering of the umbrella takes a relatively long time. If improvements in the wind-up mechanism are to be directed to saving time and effort by reducing the number of turns for completing the raising or lowering operation, some ideas come ready to mind to one skilled in this art. For instance, a larger diameter wind-up shaft could be employed. In typical, presently available lawn umbrellas, this wind-up shaft extends transversely across the hollow interior of the umbrella pole, and is connected to the wind-up handle. When the handle is turned, the wind-up shaft is turned and the cord inside the pole is wound around the shaft. Increasing the diameter of the wind-up shaft from the standard 1/4 inch (6.35 mm) would reduce the number of turns required to raise or lower the umbrella. However, such increase in the diameter of the wind-up shaft necessitates a deviation from the size of shaft normally used by this industry. Moreover, if the wind-up shaft were to substantially increase in diameter, it would be more difficult to wind the cord around the shaft inside the pole, inasmuch as there is only a limited amount of space within the pole for winding purposes.
Other changes which could be employed to reduce the number of turns for raising or lowering the umbrella include an increase in the size of the cord or an increase in the inside diameter of the pole to accommodate a larger wind-up shaft. Once again, such changes along these lines would involve a deviation from standard components known and used by the outdoor umbrella industry.
Furthermore, some manufacturers of outdoor umbrellas provide umbrella poles which have various ornamental designs around the outside diameter. In order to accommodate these ornamental or fancy designs, it is often necessary to reduce the inside diameter of the pole so as to provide greater wall thickness with which to create such ornamental designs. If the inside diameter of the umbrella pole is reduced, it would be very difficult to increase the diameter of the wind-up shaft in order to reduce the number of turns for raising or lowering the umbrella.
Different handle or crank mechanisms may be employed for raising or lowering the umbrella cover. For instance the garden umbrella described in U.S. Pat. No. 3,744,503 employs a sliding lever mechanism associated with a cable extending inside the umbrella pole in order to open the umbrella from a closed position. The inventors of U.S. Pat. No. 3,744,503 suggest that the sliding lever mechanism for opening the umbrella is an improvement over standard rotatable crank umbrellas which take a long time to open or close in view of the large number of revolutions of the crank. On the other hand, the umbrella raising mechanism of this patent leaves all of the work to the individual who is operating the umbrella. Specifically, movement of the lever to open the umbrella requires force by the individual user of sufficient magnitude to pull the entire weight of the umbrella cover from the closed position to the open position. Thus, the sliding lever mechanism does not provide the same type of mechanical advantage attributed to a rotatable crank mechanism, irrespective of the number of revolutions required to raise the umbrella. Such mechanical advantage of a rotating crank mechanism is typified by a fishing reel device such as that described in U.S. Pat. No. 2,691,492.
It can be seen that improvements are still being sought in rotatable handle wind-up mechanisms for raising and lowering umbrellas suitable for outdoor use. In particular, improvements are needed in the time required to raise or lower the umbrella, while at the same time reducing the number of revolutions of the wind-up handle for completing the raising or lowering operations. It is to such improvements, and other improvements as well, that the present invention is directed.